linux-kernel - Re: [PATCH v2 1/4] kernfs: kvmalloc xattr value instead of kmalloc

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Message-ID: <20200309195104.GA77841@mtj.thefacebook.com>
Date:   Mon, 9 Mar 2020 15:51:20 -0400
From:   Tejun Heo <tj@...nel.org>
To:     Joe Perches <joe@...ches.com>
Cc:     Daniel Xu <dxu@...uu.xyz>, cgroups@...r.kernel.org,
        lizefan@...wei.com, hannes@...xchg.org, shakeelb@...gle.com,
        linux-kernel@...r.kernel.org, gregkh@...uxfoundation.org,
        kernel-team@...com
Subject: Re: [PATCH v2 1/4] kernfs: kvmalloc xattr value instead of kmalloc

On Mon, Mar 09, 2020 at 12:41:05PM -0700, Joe Perches wrote:
> If the need is to allocate from a single block of memory,
> perhaps you need a submemory allocator like gen_pool.
> (gennalloc.h)
> 
> Dunno.  Maybe i just don't quite understand your need.

vmalloc is the right thing to do here. vmalloc space isn't a scarce
resource on any 64bit machines. On 32bits, which basically are tiny
machines at this point, these allocations are both size and quantity
limited by other factors (e.g. each cgroup consumes way more memory).

-- 
tejun